Table Of Contents
distribute-list in (RIP, IGRP, EIGRP)
distribute-list out (RIP, IGRP, EIGRP)
ip authentication key-chain eigrp
EIGRP Commands
Use the commands in this chapter to configure and monitor Enhanced Interior Gateway Routing Protocol (EIGRP). For configuration information and examples, refer to the "Configuring EIGRP" chapter of the Cisco IOS IP and IP Routing Configuration Guide.
auto-summary (EIGRP)
To restore the default behavior of automatic summarization of subnet routes into network-level routes, use the auto-summary command in router configuration mode. To disable this function and send subprefix routing information across classful network boundaries, use the no form of this command.
auto-summary
no auto-summary
Syntax Description
This command has no arguments or keywords.
Defaults
The behavior of this command is enabled by default (the software summarizes subprefixes to the classful network boundary when crossing classful network boundaries).
Command Modes
Router configuration
Command History
Usage Guidelines
Route summarization reduces the amount of routing information in the routing tables.
By default, BGP does not accept subnets redistributed from IGP. To advertise and carry subnet routes in BGP, use an explicit network command or the no auto-summary command. If you disable auto-summarization and have not entered a network command, you will not advertise network routes for networks with subnet routes unless they contain a summary route.
EIGRP summary routes are given an administrative distance value of 5. You cannot configure this value.
RIP Version 1 always uses automatic summarization. If you are using RIP Version 2, you can turn off automatic summarization by specifying the no auto-summary command. Disable automatic summarization if you must perform routing between disconnected subnets. When automatic summarization is off, subnets are advertised.
Examples
The following example disables automatic summarization for EIGRP process 109:
router eigrp 109no auto-summaryRelated Commands
clear ip eigrp neighbors
To delete entries from the neighbor table, use the clear ip eigrp neighbors command in EXEC mode.
clear ip eigrp neighbors [ip-address | type number]
Syntax Description
Command Modes
EXEC
Command History
Examples
The following example removes the neighbor whose address is 160.20.8.3:
Router# clear ip eigrp neighbors 160.20.8.3Related Commands
default-information
To control the candidate default routing information between IGRP or EIGRP processes, use the default-information command in router configuration mode. To suppress IGRP or EIGRP candidate information in incoming or outbound updates, use the no default-information in command.
default-information {in | out} {access-list-number | name}
no default-information {in | out}
Syntax Description
Defaults
Normally, exterior routes are always accepted and default information is passed between IGRP or EIGRP processes when doing redistribution.
Command Modes
Router configuration
Command History
10.0
This command was introduced.
11.2
The access-list-number and name arguments were added.
Usage Guidelines
The default network of 0.0.0.0 used by RIP cannot be redistributed by IGRP but can be redistributed by EIGRP.
Examples
The following example allows IGRP exterior or default routes to be received by the IGRP process in autonomous system 23:
router igrp 23default-information inThe following example allows EIGRP exterior or default routes to be received by the EIGRP process in autonomous system 23:
router eigrp 23default-information indefault-metric (EIGRP)
To set metrics for Interior Gateway Routing Protocol (IGRP) or EIGRP, use the default-metric command in router configuration mode. To remove the metric value and restore the default state, use the no form of this command.
default-metric bandwidth delay reliability loading mtu
no default-metric bandwidth delay reliability loading mtu
Syntax Description
Defaults
Only connected routes can be redistributed without a default metric. The metric of redistributed connected routes is set to 0.
Command Modes
Router configuration
Command History
Usage Guidelines
A default metric is required to redistribute a protocol into IGRP or EIGRP, unless you use the redistribute command. Automatic metric translations occur between IGRP and EIGRP. You do not need default metrics to redistributed IGRP or EIGRP into itself.
Note
The default metric command does not affect EIGRP-to-EIGRP or IGRP-to-EIGRP distribution. To configure EIGRP-to-EIGRP or IGRP-to-EIGRP distribution, use route maps.
Metric defaults have been carefully set to work for a wide variety of networks. Take great care when changing these values. Keeping the same metrics is supported only when redistributing from IGRP, EIGRP, or static routes.
Note
Examples
The following example takes redistributed RIP metrics and translates them into IGRP metrics with values as follows: bandwidth = 1000, delay = 100, reliability = 250, loading = 100, and mtu =1500.
router igrp 109network 131.108.0.0redistribute ripdefault-metric 1000 100 250 100 1500Related Commands
redistribute (IP)
Redistributes routes from one routing domain into another routing domain.
distance eigrp
To allow the use of two administrative distances—internal and external—that could be a better route to a node, use the distance eigrp command in router configuration mode. To reset these values to their defaults, use the no form of this command.
distance eigrp internal-distance external-distance
no distance eigrp
Syntax Description
Defaults
internal-distance: 90
external-distance: 170
Command Modes
Router configuration
Command History
Usage Guidelines
An administrative distance is a rating of the trustworthiness of a routing information source, such as an individual router or a group of routers. Numerically, an administrative distance is an integer between 0 and 255. In general, the higher the value, the lower the trust rating. An administrative distance of 255 means the routing information source cannot be trusted at all and should be ignored.
Use the distance eigrp command if another protocol is known to be able to provide a better route to a node than was actually learned via external EIGRP or if some internal routes should really be preferred by EIGRP.
Table 59 lists the default administrative distances.
To display the default administrative distance for a specified routing process, use the show ip protocols EXEC command.
Examples
In the following example, the router eigrp global configuration command sets up EIGRP routing in autonomous system number 109. The network router configuration commands specify EIGRP routing on networks 192.168.7.0 and 172.16.0.0. The distance eigrp command sets the administrative distance of all EIGRP internal routes to 80 and all EIGRP external routes to 130.
Router(config)# router eigrp 109Router(config-router)# network 192.168.7.0Router(config-router)# network 172.16.0.0Router(config-router)# distance eigrp 80 130Router(config-router)# distance eigrp 80 130
Note
Related Commands
show ip protocols
Displays the parameters and current state of the active routing protocol process.
distribute-list in (RIP, IGRP, EIGRP)
To filter networks received in updates, use the distribute-list in command in address family or router configuration mode. To disable this function, use the no form of this command.
distribute-list {access-list-number | prefix prefix-list-name [gateway prefix-list-name]} in [interface-type interface-number]
no distribute-list {access-list-number | prefix prefix-list-name [gateway prefix-list-name]} in [interface-type interface-number]
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Address family configuration
Router configuration
Command History
Usage Guidelines
This command is not supported in Intermediate System-to-Intermediate System (IS-IS) or Open Shortest Path First (OSPF).
Using a prefix list allows filtering based upon the prefix length, making it possible to filter either on the prefix list, the gateway, or both for incoming updates.
Specify either an access list or a prefix list with the distribute-list in command.
Use the gateway keyword only with the prefix-list keyword.
To suppress networks from being advertised in updates, use the distribute-list out command.
Examples
In the following example, the BGP routing process accepts only two networks—network 0.0.0.0 and network 131.108.0.0:
access-list 1 permit 0.0.0.0access-list 1 permit 131.108.0.0access-list 1 deny 0.0.0.0 255.255.255.255router bgpnetwork 131.108.0.0distribute-list 1 inIn the following example, The RIP process accepts only prefixes with prefix lengths of /8 to /24:
ip prefix-list max24 seq 5 permit 0.0.0.0/0 ge 8 le 24router ripnetwork 131.108.0.0distribute-list prefix max24 inIn the following example, the RIP process filters on packet length and accepts routing updates from address 192.1.1.1 only:
ip prefix-list max24 seq 5 permit 0.0.0.0/0 ge 8 le 24ip prefix-list allowlist seq5 permit 192.1.1.1/32router ripnetwork 131.108.0.0distribute-list prefix max24 gateway allowlist inRelated Commands
distribute-list out (RIP, IGRP, EIGRP)
To suppress networks from being advertised in updates, use the distribute-list out command in address family or router configuration mode. To disable this function, use the no form of this command.
distribute-list {access-list-number | prefix prefix-list-name [gateway prefix-list-name]} out [interface-name | routing-process | as-number]
no distribute-list {access-list-number | prefix prefix-list-name [gateway prefix-list-name]} out [interface-name | routing-process | as-number]
Syntax Description
Defaults
This command is disabled by default.
Command Modes
Address family configuration
Router configuration
Command History
Usage Guidelines
When redistributing networks, a routing process name can be specified as an optional trailing argument to the distribute-list command. Specifying an argument causes the access list or prefix list to be applied to only those routes derived from the specified routing process. After the process-specific access list or prefix list is applied, any access list or prefix list specified by a distribute-list command without a process name argument will be applied. Addresses not specified in the distribute-list command will not be advertised in outgoing routing updates.
Specify either an access list or a prefix list with the distribute-list in command.
Use the gateway keyword only with the prefix-list keyword.
Note
Examples
The following example causes only one network (network 131.108.0.0) to be advertised by a RIP routing process:
access-list 1 permit 131.108.0.0access-list 1 deny 0.0.0.0 255.255.255.255router ripnetwork 131.108.0.0distribute-list 1 outRelated Commands
access-list (IP extended)
Defines an extended IP access list.
Filters networks received in updates.
ip prefix-list
Creates an entry in a prefix list.
eigrp log-neighbor-changes
To enable the logging of changes in Enhanced Interior Gateway Routing Protocol (EIGRP) neighbor adjacencies, use the eigrp log-neighbor-change command in router configuration mode. To disable the logging of changes in EIGRP neighbor adjacencies, use the no form of this command.
eigrp log-neighbor-changes
no eigrp log-neighbor-changes
Syntax Description
This command has no arguments or keywords.
Defaults
Adjacency changes are logged.
Command Modes
Router configuration
Command History
Usage Guidelines
This command enables the logging of neighbor adjacency changes to monitor the stability of the routing system and to help detect problems. Logging is enabled by default. To disable the logging of neighbor adjacency changes, use the no form of this command.
Examples
The following configuration disables logging of neighbor changes for EIGRP process 209:
router eigrp 209no eigrp log-neighbor-changesThe following configuration enables logging of neighbor changes for EIGRP process 209:
router eigrp 209eigrp log-neighbor-changeseigrp log-neighbor-warnings
To enable the logging of Enhanced Interior Gateway Routing Protocol (EIGRP) neighbor warning messages, use the eigrp log-neighbor-warnings command in router configuration mode. To disable the logging of EIGRP neighbor warning messages, use the no form of this command.
eigrp log-neighbor-warnings [seconds]
no eigrp log-neighbor-changes
Syntax Description
seconds
(Optional) The time interval in seconds between repeated neighbor warning messages. The range of seconds is 1-65535.
Defaults
Neighbor warning messages are logged.
Command Modes
Router configuration
Command History
Usage Guidelines
When neighbor warning messages occur, they are logged by default. With this command, you can disable and enable neighbor warning messages, and configure the interval between repeated neighbor warning messages.
Examples
The following command will log neighbor warning messages for EIGRP process 209 and repeat the warning messages in 5-minute (300 seconds) intervals:
router eigrp 209eigrp log-neighbor-warnings 300eigrp router-id
To set the router ID used by Enhanced Interior Gateway Routing Protocol (EIGRP) when communicating with its neighbors, use the eigrp router-id command in router configuration mode. To remove the configured router ID, use the no form of this command.
eigrp router-id ip-address
no eigrp router-id ip-address
Syntax Description
Defaults
EIGRP automatically selects an IP address to use as the router ID when an EIGRP process is started. The highest local IP address is selected and loopback interfaces are preferred. The router ID is not changed unless the EIGRP process is removed with the no router eigrp command or if the router ID is manually configured with the eigrp router-id command.
Command Modes
Address family configuration
Router configurationCommand History
Usage Guidelines
The router ID is used to identify the originating router for external routes. If an external route is received with the local router ID, the route is discarded. The router ID can be configured with any IP address with two exceptions; 0.0.0.0 and 255.255.255.255 are not legal values and cannot be entered. A unique value should be configured for each router.
Examples
The following example configures 172.16.1.3 as a fixed router ID:
router eigrp 209eigrp router-id 172.16.1.3eigrp stub
To configure a router as a stub using Enhanced Interior Gateway Routing Protocol (EIGRP), use the eigrp stub command in router configuration mode. To disable the EIGRP stub routing feature, use the no form of this command.
eigrp stub [receive-only | connected | static | summary]
no eigrp stub [receive-only | connected | static | summary]
Syntax Description
Defaults
Stub routing is not enabled by default.
Command Modes
Router configuration
Command History
12.0(7)T
This command was introduced.
12.0(15)S
This command was integrated into Cisco IOS Release 12.0(15)S.
Usage Guidelines
Use the eigrp stub command to configure a router as a stub where the router directs all IP traffic to a distribution router.
The eigrp stub command can be modified with several options, and these options can be used in any combination except for the receive-only keyword. The receive-only keyword will restrict the router from sharing any of its routes with any other router in that EIGRP autonomous system, and the receive-only keyword will not permit any other option to be specified because it prevents any type of route from being sent. The three other optional keywords (connected, static, and summary) can be used in any combination but cannot be used with the receive-only keyword. If any of these three keywords is used individually with the eigrp stub command, connected and summary routes will not be sent automatically.
The connected keyword will permit the EIGRP Stub Routing feature to send connected routes. If the connected routes are not covered by a network statement, it may be necessary to redistribute connected routes with the redistribute connected command under the EIGRP process. This option is enabled by default.
The static keyword will permit the EIGRP Stub Routing feature to send static routes. Without the configuration of this option, EIGRP will not send any static routes, including internal static routes that normally would be automatically redistributed. It will still be necessary to redistribute static routes with the redistribute static command.
The summary keyword will permit the EIGRP Stub Routing feature to send summary routes. Summary routes can be created manually with the summary address command or automatically at a major network border router with the auto-summary command enabled. This option is enabled by default.
Note
Examples
In the following example, the eigrp stub command is used to configure the router as a stub that advertises connected and summary routes:
router eigrp 1network 10.0.0.0eigrp stubIn the following example, the eigrp stub command is issued with the connected and static keywords to configure the router as a stub that advertises connected and static routes (sending summary routes will not be permitted):
router eigrp 1network 10.0.0.0eigrp stub connected staticIn the following example, the eigrp stub command is issued with the receive-only keyword to configure the router as a receive-only neighbor (connected, summary, and static routes will not be sent):
router eigrp 1network 10.0.0.0 eigrpeigrp stub receive-onlyip authentication key-chain eigrp
To enable authentication of Enhanced Interior Gateway Routing Protocol (IGRP) packets, use the ip authentication key-chain eigrp interface configuration command. To disable such authentication, use the no form of this command.
ip authentication key-chain eigrp autonomous-system key-chain
no ip authentication key-chain eigrp autonomous-system key-chain
Syntax Description
autonomous-system
Autonomous system to which the authentication applies.
key-chain
Name of the authentication key chain.
Defaults
No authentication is provided for EIGRP packets.
Command Modes
Interface configuration
Command History
Examples
The following example applies authentication to autonomous system 2 and identifies a key chain named SPORTS:
ip authentication key-chain eigrp 2 SPORTSRelated Commands
ip authentication mode eigrp
To specify the type of authentication used in Enhanced Interior Gateway Routing Protocol (EIGRP) packets, use the ip authentication mode eigrp interface configuration command. To disable that type of authentication, use the no form of this command.
ip authentication mode eigrp autonomous-system md5
no ip authentication mode eigrp autonomous-system md5
Syntax Description
Defaults
No authentication is provided for EIGRP packets.
Command Modes
Interface configuration
Command History
Usage Guidelines
Configure authentication to prevent unapproved sources from introducing unauthorized or false routing messages. When authentication is configured, an Message Digest 5 (MD5) keyed digest is added to each EIGRP packet in the specified autonomous system.
Examples
The following example configures the interface to use MD5 authentication in EIGRP packets in autonomous system 10:
ip authentication mode eigrp 10 md5Related Commands
ip bandwidth-percent eigrp
To configure the percentage of bandwidth that may be used by Enhanced Interior Gateway Routing Protocol (EIGRP) on an interface, use the ip bandwidth-percent eigrp interface configuration command. To restore the default value, use the no form of this command.
ip bandwidth-percent eigrp as-number percent
no ip bandwidth-percent eigrp as-number percent
Syntax Description
Defaults
50 percent
Command Modes
Interface configuration
Command History
Usage Guidelines
EIGRP will use up to 50 percent of the bandwidth of a link, as defined by the bandwidth interface configuration command. This command may be used if some other fraction of the bandwidth is desired. Note that values greater than 100 percent may be configured; this may be useful if the bandwidth is set artificially low for other reasons.
Examples
The following example allows EIGRP to use up to 75 percent (42 kbps) of a 56-kbps serial link in autonomous system 209:
interface serial 0bandwidth 56ip bandwidth-percent eigrp 209 75Related Commands
ip hello-interval eigrp
To configure the hello interval for the Enhanced Interior Gateway Routing Protocol (EIGRP) routing process designated by an autonomous system number, use the ip hello-interval eigrp interface configuration command. To restore the default value, use the no form of this command.
ip hello-interval eigrp autonomous-system-number seconds
no ip hello-interval eigrp autonomous-system-number seconds
Syntax Description
Defaults
For low-speed, NBMA networks: 60 seconds
For all other networks: 5 seconds
Command Modes
Interface configuration
Command History
Usage Guidelines
The default of 60 seconds applies only to low-speed, nonbroadcast multiaccess (NBMA) media. Low speed is considered to be a rate of T1 or slower, as specified with the bandwidth interface configuration command. Note that for the purposes of EIGRP, Frame Relay and SMDS networks may or may not be considered to be NBMA. These networks are considered NBMA if the interface has not been configured to use physical multicasting; otherwise, they are considered not to be NBMA.
Examples
The following example sets the hello interval for Ethernet interface 0 to 10 seconds:
interface ethernet 0ip hello-interval eigrp 109 10Related Commands
bandwidth
Sets a bandwidth value for an interface.
Configures the hold time for a particular EIGRP routing process designated by the autonomous system number.
ip hold-time eigrp
To configure the hold time for a particular Enhanced Interior Gateway Routing Protocol (EIGRP) routing process designated by the autonomous system number, use the ip hold-time eigrp interface configuration command. To restore the default value, use the no form of this command.
ip hold-time eigrp autonomous-system-number seconds
no ip hold-time eigrp autonomous-system-number seconds
Syntax Description
Defaults
For low-speed, NBMA networks: 180 seconds
For all other networks: 15 seconds
Command Modes
Interface configuration
Command History
Usage Guidelines
On very congested and large networks, the default hold time might not be sufficient time for all routers and access servers to receive hello packets from their neighbors. In this case, you may want to increase the hold time.
We recommend that the hold time be at least three times the hello interval. If a router does not receive a hello packet within the specified hold time, routes through this router are considered unavailable.
Increasing the hold time delays route convergence across the network.
The default of 180 seconds hold time and 60 seconds hello interval apply only to low-speed, nonbroadcast multiaccess (NBMA) media. Low speed is considered to be a rate of T1 or slower, as specified with the bandwidth interface configuration command.
Examples
The following example sets the hold time for Ethernet interface 0 to 40 seconds:
interface ethernet 0ip hold-time eigrp 109 40Related Commands
bandwidth
Sets a bandwidth value for an interface.
Configures the hello interval for the EIGRP routing process designated by an autonomous system number.
ip split-horizon eigrp
To enable Enhanced Interior Gateway Routing Protocol (EIGRP) split horizon, use the ip split-horizon eigrp interface configuration command. To disable split horizon, use the no form of this command.
ip split-horizon eigrp autonomous-system-number
no ip split-horizon eigrp autonomous-system-number
Syntax Description
Defaults
The behavior of this command is enabled by default.
Command Modes
Interface configuration
Command History
Usage Guidelines
For networks that include links over X.25 PSNs, you can use the neighbor router configuration command to defeat the split horizon feature. As an alternative, you can explicitly specify the no ip split-horizon eigrp command in your configuration. However, if you do so, you must similarly disable split horizon for all routers and access servers in any relevant multicast groups on that network.
Note
Examples
The following example disables split horizon on a serial link connected to an X.25 network:
interface serial 0encapsulation x25no ip split-horizon eigrp 101Related Commands
ip split-horizon (EIGRP)
Enables the split horizon mechanism.
neighbor (EIGRP)
Defines a neighboring router with which to exchange routing information.
ip summary-address eigrp
To configure a summary aggregate address for a specified interface, use the ip summary-address eigrp interface configuration command. To disable a configuration, use the no form of this command.
ip summary-address eigrp autonomous-system-number network-address subnet-mask [admin-distance]
no ip summary-address eigrp autonomous-system-number network-address subnet-mask [admin-distance]
Syntax Description
Defaults
No summary aggregate addresses are predefined. The default administrative distance metric for Enhanced Interior Gateway Routing Protocol (EIGRP) is 90.
Command Modes
Interface configuration
Command History
10.0
This command was introduced.
12.0(7)T
The admin-distance argument was added.
Usage Guidelines
EIGRP summary routes are given an administrative distance value of 5. The administrative distance metric is used to advertise a summary without installing it in the routing table.
Examples
The following example sets the IP summary aggregate address for Ethernet interface 0 with an administrative distance of 95:
interface ethernet 0ip summary-address eigrp 109 192.1.0.0 255.255.0.0 95Related Commands
Restores the default behavior of automatic summarization of subnet routes into network-level routes.
metric weights (EIGRP)
To allow the tuning of the Interior Gateway Routing Protocol (IGRP) or Enhanced Interior Gateway Routing Protocol (EIGRP) metric calculations, use the metric weights command in router configuration mode. To reset the values to their defaults, use the no form of this command.
metric weights tos k1 k2 k3 k4 k5
no metric weights
Syntax Description
tos
Type of service must always be zero.
k1k2 k3 k4 k5
Constants that convert an IGRP or EIGRP metric vector into a scalar quantity.
Defaults
tos: 0
k1: 1
k2: 0
k3: 1
k4: 0
k5: 0
Command Modes
Router configuration
Command History
Usage Guidelines
Use this command to alter the default behavior of EIGRP or IGRP routing and metric computation and allow the tuning of the metric calculation for a particular type of service (ToS).
If k5 equals 0, the composite IGRP or EIGRP metric is computed according to the following formula:
metric = [k1 * bandwidth + (k2 * bandwidth)/(256 - load) + k3 * delay]If k5 does not equal zero, an additional operation is done:
metric = metric * [k5 / (reliability + k4)]Bandwidth is inverse minimum bandwidth of the path in bits per second scaled by a factor of 2.56 ¥ 1012. The range is from a 1200-bps line to 10 terabits per second.
Delay is in units of 10 microseconds. This gives a range of 10 microseconds to 168 seconds. A delay of all ones indicates that the network is unreachable.
The delay parameter is stored in a 32-bit field, in increments of 39.1 nanoseconds. This gives a range of 1 (39.1 nanoseconds) to hexadecimal FFFFFFFF (decimal 4,294,967,040 nanoseconds). A delay of all ones (that is, a delay of hexadecimal FFFFFFFF) indicates that the network is unreachable.
Table 60 lists the default values used for several common media.
